/*
 * Wi-Fi Protected Setup - Enrollee
 * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto/crypto.h"
#include "crypto/sha256.h"
#include "wps_i.h"
#include "wps_dev_attr.h"


static int wps_build_mac_addr(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * MAC Address");
    wpabuf_put_be16(msg, ATTR_MAC_ADDR);
    wpabuf_put_be16(msg, ETH_ALEN);
    wpabuf_put_data(msg, wps->mac_addr_e, ETH_ALEN);
    return 0;
}


static int wps_build_wps_state(struct wps_data *wps, struct wpabuf *msg)
{
    u8 state;
    if (wps->wps->ap)
        state = wps->wps->wps_state;
    else
        state = WPS_STATE_NOT_CONFIGURED;
    wpa_printf(MSG_DEBUG, "WPS:  * Wi-Fi Protected Setup State (%d)",
            state);
    wpabuf_put_be16(msg, ATTR_WPS_STATE);
    wpabuf_put_be16(msg, 1);
    wpabuf_put_u8(msg, state);
    return 0;
}


static int wps_build_e_hash(struct wps_data *wps, struct wpabuf *msg)
{
    u8 *hash;
    const u8 *addr[4];
    size_t len[4];

    if (os_get_random(wps->snonce, 2 * WPS_SECRET_NONCE_LEN) < 0)
        return -1;
    wpa_hexdump(MSG_DEBUG, "WPS: E-S1", wps->snonce, WPS_SECRET_NONCE_LEN);
    wpa_hexdump(MSG_DEBUG, "WPS: E-S2",
            wps->snonce + WPS_SECRET_NONCE_LEN, WPS_SECRET_NONCE_LEN);

    if (wps->dh_pubkey_e == NULL || wps->dh_pubkey_r == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: DH public keys not available for "
                "E-Hash derivation");
        return -1;
    }

    wpa_printf(MSG_DEBUG, "WPS:  * E-Hash1");
    wpabuf_put_be16(msg, ATTR_E_HASH1);
    wpabuf_put_be16(msg, SHA256_MAC_LEN);
    hash = wpabuf_put(msg, SHA256_MAC_LEN);
    /* E-Hash1 = HMAC_AuthKey(E-S1 || PSK1 || PK_E || PK_R) */
    addr[0] = wps->snonce;
    len[0] = WPS_SECRET_NONCE_LEN;
    addr[1] = wps->psk1;
    len[1] = WPS_PSK_LEN;
    addr[2] = wpabuf_head(wps->dh_pubkey_e);
    len[2] = wpabuf_len(wps->dh_pubkey_e);
    addr[3] = wpabuf_head(wps->dh_pubkey_r);
    len[3] = wpabuf_len(wps->dh_pubkey_r);
    hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);
    wpa_hexdump(MSG_DEBUG, "WPS: E-Hash1", hash, SHA256_MAC_LEN);

    wpa_printf(MSG_DEBUG, "WPS:  * E-Hash2");
    wpabuf_put_be16(msg, ATTR_E_HASH2);
    wpabuf_put_be16(msg, SHA256_MAC_LEN);
    hash = wpabuf_put(msg, SHA256_MAC_LEN);
    /* E-Hash2 = HMAC_AuthKey(E-S2 || PSK2 || PK_E || PK_R) */
    addr[0] = wps->snonce + WPS_SECRET_NONCE_LEN;
    addr[1] = wps->psk2;
    hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);
    wpa_hexdump(MSG_DEBUG, "WPS: E-Hash2", hash, SHA256_MAC_LEN);

    return 0;
}


static int wps_build_e_snonce1(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * E-SNonce1");
    wpabuf_put_be16(msg, ATTR_E_SNONCE1);
    wpabuf_put_be16(msg, WPS_SECRET_NONCE_LEN);
    wpabuf_put_data(msg, wps->snonce, WPS_SECRET_NONCE_LEN);
    return 0;
}


static int wps_build_e_snonce2(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * E-SNonce2");
    wpabuf_put_be16(msg, ATTR_E_SNONCE2);
    wpabuf_put_be16(msg, WPS_SECRET_NONCE_LEN);
    wpabuf_put_data(msg, wps->snonce + WPS_SECRET_NONCE_LEN,
            WPS_SECRET_NONCE_LEN);
    return 0;
}


static struct wpabuf * wps_build_m1(struct wps_data *wps)
{
    struct wpabuf *msg;

    if (os_get_random(wps->nonce_e, WPS_NONCE_LEN) < 0)
        return NULL;
    wpa_hexdump(MSG_DEBUG, "WPS: Enrollee Nonce",
            wps->nonce_e, WPS_NONCE_LEN);

    wpa_printf(MSG_DEBUG, "WPS: Building Message M1");
    msg = wpabuf_alloc(1000);
    if (msg == NULL)
        return NULL;

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M1) ||
            wps_build_uuid_e(msg, wps->uuid_e) ||
            wps_build_mac_addr(wps, msg) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_public_key(wps, msg) ||
            wps_build_auth_type_flags(wps, msg) ||
            wps_build_encr_type_flags(wps, msg) ||
            wps_build_conn_type_flags(wps, msg) ||
            wps_build_config_methods(msg, wps->wps->config_methods) ||
            wps_build_wps_state(wps, msg) ||
            wps_build_device_attrs(&wps->wps->dev, msg) ||
            wps_build_rf_bands(&wps->wps->dev, msg) ||
            wps_build_assoc_state(wps, msg) ||
            wps_build_dev_password_id(msg, wps->dev_pw_id) ||
            wps_build_config_error(msg, WPS_CFG_NO_ERROR) ||
            wps_build_os_version(&wps->wps->dev, msg)) {
        wpabuf_free(msg);
        return NULL;
    }

    wps->state = RECV_M2;
    return msg;
}


static struct wpabuf * wps_build_m3(struct wps_data *wps)
{
    struct wpabuf *msg;

    wpa_printf(MSG_DEBUG, "WPS: Building Message M3");

    if (wps->dev_password == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Device Password available");
        return NULL;
    }
    wps_derive_psk(wps, wps->dev_password, wps->dev_password_len);

    msg = wpabuf_alloc(1000);
    if (msg == NULL)
        return NULL;

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M3) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_e_hash(wps, msg) ||
            wps_build_authenticator(wps, msg)) {
        wpabuf_free(msg);
        return NULL;
    }

    wps->state = RECV_M4;
    return msg;
}


static struct wpabuf * wps_build_m5(struct wps_data *wps)
{
    struct wpabuf *msg, *plain;

    wpa_printf(MSG_DEBUG, "WPS: Building Message M5");

    plain = wpabuf_alloc(200);
    if (plain == NULL)
        return NULL;

    msg = wpabuf_alloc(1000);
    if (msg == NULL) {
        wpabuf_free(plain);
        return NULL;
    }

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M5) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_e_snonce1(wps, plain) ||
            wps_build_key_wrap_auth(wps, plain) ||
            wps_build_encr_settings(wps, msg, plain) ||
            wps_build_authenticator(wps, msg)) {
        wpabuf_free(plain);
        wpabuf_free(msg);
        return NULL;
    }
    wpabuf_free(plain);

    wps->state = RECV_M6;
    return msg;
}


static int wps_build_cred_ssid(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * SSID");
    wpabuf_put_be16(msg, ATTR_SSID);
    wpabuf_put_be16(msg, wps->wps->ssid_len);
    wpabuf_put_data(msg, wps->wps->ssid, wps->wps->ssid_len);
    return 0;
}


static int wps_build_cred_auth_type(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type");
    wpabuf_put_be16(msg, ATTR_AUTH_TYPE);
    wpabuf_put_be16(msg, 2);
    wpabuf_put_be16(msg, wps->wps->auth_types);
    return 0;
}


static int wps_build_cred_encr_type(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type");
    wpabuf_put_be16(msg, ATTR_ENCR_TYPE);
    wpabuf_put_be16(msg, 2);
    wpabuf_put_be16(msg, wps->wps->encr_types);
    return 0;
}


static int wps_build_cred_network_key(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * Network Key");
    wpabuf_put_be16(msg, ATTR_NETWORK_KEY);
    wpabuf_put_be16(msg, wps->wps->network_key_len);
    wpabuf_put_data(msg, wps->wps->network_key, wps->wps->network_key_len);
    return 0;
}


static int wps_build_cred_mac_addr(struct wps_data *wps, struct wpabuf *msg)
{
    wpa_printf(MSG_DEBUG, "WPS:  * MAC Address (AP BSSID)");
    wpabuf_put_be16(msg, ATTR_MAC_ADDR);
    wpabuf_put_be16(msg, ETH_ALEN);
    wpabuf_put_data(msg, wps->wps->dev.mac_addr, ETH_ALEN);
    return 0;
}


static int wps_build_ap_settings(struct wps_data *wps, struct wpabuf *plain)
{
    if (wps->wps->ap_settings) {
        wpa_printf(MSG_DEBUG, "WPS:  * AP Settings (pre-configured)");
        wpabuf_put_data(plain, wps->wps->ap_settings,
                wps->wps->ap_settings_len);
        return 0;
    }

    return wps_build_cred_ssid(wps, plain) ||
        wps_build_cred_mac_addr(wps, plain) ||
        wps_build_cred_auth_type(wps, plain) ||
        wps_build_cred_encr_type(wps, plain) ||
        wps_build_cred_network_key(wps, plain);
}


static struct wpabuf * wps_build_m7(struct wps_data *wps)
{
    struct wpabuf *msg, *plain;

    wpa_printf(MSG_DEBUG, "WPS: Building Message M7");

    plain = wpabuf_alloc(500 + wps->wps->ap_settings_len);
    if (plain == NULL)
        return NULL;

    msg = wpabuf_alloc(1000 + wps->wps->ap_settings_len);
    if (msg == NULL) {
        wpabuf_free(plain);
        return NULL;
    }

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M7) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_e_snonce2(wps, plain) ||
            (wps->wps->ap && wps_build_ap_settings(wps, plain)) ||
            wps_build_key_wrap_auth(wps, plain) ||
            wps_build_encr_settings(wps, msg, plain) ||
            wps_build_authenticator(wps, msg)) {
        wpabuf_free(plain);
        wpabuf_free(msg);
        return NULL;
    }
    wpabuf_free(plain);

    if (wps->wps->ap && wps->wps->registrar) {
        /*
         * If the Registrar is only learning our current configuration,
         * it may not continue protocol run to successful completion.
         * Store information here to make sure it remains available.
         */
        wps_device_store(wps->wps->registrar, &wps->peer_dev,
                wps->uuid_r);
    }

    wps->state = RECV_M8;
    return msg;
}


static struct wpabuf * wps_build_wsc_done(struct wps_data *wps)
{
    struct wpabuf *msg;

    wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_Done");

    msg = wpabuf_alloc(1000);
    if (msg == NULL)
        return NULL;

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_WSC_DONE) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg)) {
        wpabuf_free(msg);
        return NULL;
    }

    if (wps->wps->ap)
        wps->state = RECV_ACK;
    else {
        wps_success_event(wps->wps);
        wps->state = WPS_FINISHED;
    }
    return msg;
}


static struct wpabuf * wps_build_wsc_ack(struct wps_data *wps)
{
    struct wpabuf *msg;

    wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK");

    msg = wpabuf_alloc(1000);
    if (msg == NULL)
        return NULL;

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_WSC_ACK) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg)) {
        wpabuf_free(msg);
        return NULL;
    }

    return msg;
}


static struct wpabuf * wps_build_wsc_nack(struct wps_data *wps)
{
    struct wpabuf *msg;

    wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK");

    msg = wpabuf_alloc(1000);
    if (msg == NULL)
        return NULL;

    if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_WSC_NACK) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_config_error(msg, wps->config_error)) {
        wpabuf_free(msg);
        return NULL;
    }

    return msg;
}


struct wpabuf * wps_enrollee_get_msg(struct wps_data *wps,
        enum wsc_op_code *op_code)
{
    struct wpabuf *msg;

    switch (wps->state) {
        case SEND_M1:
            msg = wps_build_m1(wps);
            *op_code = WSC_MSG;
            break;
        case SEND_M3:
            msg = wps_build_m3(wps);
            *op_code = WSC_MSG;
            break;
        case SEND_M5:
            msg = wps_build_m5(wps);
            *op_code = WSC_MSG;
            break;
        case SEND_M7:
            msg = wps_build_m7(wps);
            *op_code = WSC_MSG;
            break;
        case RECEIVED_M2D:
            if (wps->wps->ap) {
                msg = wps_build_wsc_nack(wps);
                *op_code = WSC_NACK;
                break;
            }
            msg = wps_build_wsc_ack(wps);
            *op_code = WSC_ACK;
            if (msg) {
                /* Another M2/M2D may be received */
                wps->state = RECV_M2;
            }
            break;
        case SEND_WSC_NACK:
            msg = wps_build_wsc_nack(wps);
            *op_code = WSC_NACK;
            break;
        case WPS_MSG_DONE:
            msg = wps_build_wsc_done(wps);
            *op_code = WSC_Done;
            break;
        default:
            wpa_printf(MSG_DEBUG, "WPS: Unsupported state %d for building "
                    "a message", wps->state);
            msg = NULL;
            break;
    }

    if (*op_code == WSC_MSG && msg) {
        /* Save a copy of the last message for Authenticator derivation
        */
        wpabuf_free(wps->last_msg);
        wps->last_msg = wpabuf_dup(msg);
    }

    return msg;
}


static int wps_process_registrar_nonce(struct wps_data *wps, const u8 *r_nonce)
{
    if (r_nonce == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Registrar Nonce received");
        return -1;
    }

    os_memcpy(wps->nonce_r, r_nonce, WPS_NONCE_LEN);
    wpa_hexdump(MSG_DEBUG, "WPS: Registrar Nonce",
            wps->nonce_r, WPS_NONCE_LEN);

    return 0;
}


static int wps_process_enrollee_nonce(struct wps_data *wps, const u8 *e_nonce)
{
    if (e_nonce == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Enrollee Nonce received");
        return -1;
    }

    if (os_memcmp(wps->nonce_e, e_nonce, WPS_NONCE_LEN) != 0) {
        wpa_printf(MSG_DEBUG, "WPS: Invalid Enrollee Nonce received");
        return -1;
    }

    return 0;
}


static int wps_process_uuid_r(struct wps_data *wps, const u8 *uuid_r)
{
    if (uuid_r == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No UUID-R received");
        return -1;
    }

    os_memcpy(wps->uuid_r, uuid_r, WPS_UUID_LEN);
    wpa_hexdump(MSG_DEBUG, "WPS: UUID-R", wps->uuid_r, WPS_UUID_LEN);

    return 0;
}


static int wps_process_pubkey(struct wps_data *wps, const u8 *pk,
        size_t pk_len)
{
    if (pk == NULL || pk_len == 0) {
        wpa_printf(MSG_DEBUG, "WPS: No Public Key received");
        return -1;
    }

#ifdef CONFIG_WPS_OOB
    if (wps->dev_pw_id != DEV_PW_DEFAULT &&
            wps->wps->oob_conf.pubkey_hash) {
        const u8 *addr[1];
        u8 hash[WPS_HASH_LEN];

        addr[0] = pk;
        sha256_vector(1, addr, &pk_len, hash);
        if (os_memcmp(hash,
                    wpabuf_head(wps->wps->oob_conf.pubkey_hash),
                    WPS_OOB_PUBKEY_HASH_LEN) != 0) {
            wpa_printf(MSG_ERROR, "WPS: Public Key hash error");
            return -1;
        }
    }
#endif /* CONFIG_WPS_OOB */

    wpabuf_free(wps->dh_pubkey_r);
    wps->dh_pubkey_r = wpabuf_alloc_copy(pk, pk_len);
    if (wps->dh_pubkey_r == NULL)
        return -1;

    if (wps_derive_keys(wps) < 0)
        return -1;

    return 0;
}


static int wps_process_r_hash1(struct wps_data *wps, const u8 *r_hash1)
{
    if (r_hash1 == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No R-Hash1 received");
        return -1;
    }

    os_memcpy(wps->peer_hash1, r_hash1, WPS_HASH_LEN);
    wpa_hexdump(MSG_DEBUG, "WPS: R-Hash1", wps->peer_hash1, WPS_HASH_LEN);

    return 0;
}


static int wps_process_r_hash2(struct wps_data *wps, const u8 *r_hash2)
{
    if (r_hash2 == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No R-Hash2 received");
        return -1;
    }

    os_memcpy(wps->peer_hash2, r_hash2, WPS_HASH_LEN);
    wpa_hexdump(MSG_DEBUG, "WPS: R-Hash2", wps->peer_hash2, WPS_HASH_LEN);

    return 0;
}


static int wps_process_r_snonce1(struct wps_data *wps, const u8 *r_snonce1)
{
    u8 hash[SHA256_MAC_LEN];
    const u8 *addr[4];
    size_t len[4];

    if (r_snonce1 == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No R-SNonce1 received");
        return -1;
    }

    wpa_hexdump_key(MSG_DEBUG, "WPS: R-SNonce1", r_snonce1,
            WPS_SECRET_NONCE_LEN);

    /* R-Hash1 = HMAC_AuthKey(R-S1 || PSK1 || PK_E || PK_R) */
    addr[0] = r_snonce1;
    len[0] = WPS_SECRET_NONCE_LEN;
    addr[1] = wps->psk1;
    len[1] = WPS_PSK_LEN;
    addr[2] = wpabuf_head(wps->dh_pubkey_e);
    len[2] = wpabuf_len(wps->dh_pubkey_e);
    addr[3] = wpabuf_head(wps->dh_pubkey_r);
    len[3] = wpabuf_len(wps->dh_pubkey_r);
    hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);

    if (os_memcmp(wps->peer_hash1, hash, WPS_HASH_LEN) != 0) {
        wpa_printf(MSG_DEBUG, "WPS: R-Hash1 derived from R-S1 does "
                "not match with the pre-committed value");
        wps->config_error = WPS_CFG_DEV_PASSWORD_AUTH_FAILURE;
        wps_pwd_auth_fail_event(wps->wps, 1, 1);
        return -1;
    }

    wpa_printf(MSG_DEBUG, "WPS: Registrar proved knowledge of the first "
            "half of the device password");

    return 0;
}


static int wps_process_r_snonce2(struct wps_data *wps, const u8 *r_snonce2)
{
    u8 hash[SHA256_MAC_LEN];
    const u8 *addr[4];
    size_t len[4];

    if (r_snonce2 == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No R-SNonce2 received");
        return -1;
    }

    wpa_hexdump_key(MSG_DEBUG, "WPS: R-SNonce2", r_snonce2,
            WPS_SECRET_NONCE_LEN);

    /* R-Hash2 = HMAC_AuthKey(R-S2 || PSK2 || PK_E || PK_R) */
    addr[0] = r_snonce2;
    len[0] = WPS_SECRET_NONCE_LEN;
    addr[1] = wps->psk2;
    len[1] = WPS_PSK_LEN;
    addr[2] = wpabuf_head(wps->dh_pubkey_e);
    len[2] = wpabuf_len(wps->dh_pubkey_e);
    addr[3] = wpabuf_head(wps->dh_pubkey_r);
    len[3] = wpabuf_len(wps->dh_pubkey_r);
    hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);

    if (os_memcmp(wps->peer_hash2, hash, WPS_HASH_LEN) != 0) {
        wpa_printf(MSG_DEBUG, "WPS: R-Hash2 derived from R-S2 does "
                "not match with the pre-committed value");
        wps->config_error = WPS_CFG_DEV_PASSWORD_AUTH_FAILURE;
        wps_pwd_auth_fail_event(wps->wps, 1, 2);
        return -1;
    }

    wpa_printf(MSG_DEBUG, "WPS: Registrar proved knowledge of the second "
            "half of the device password");

    return 0;
}


static int wps_process_cred_e(struct wps_data *wps, const u8 *cred,
        size_t cred_len)
{
    struct wps_parse_attr attr;
    struct wpabuf msg;

    wpa_printf(MSG_DEBUG, "WPS: Received Credential");
    os_memset(&wps->cred, 0, sizeof(wps->cred));
    wpabuf_set(&msg, cred, cred_len);
    if (wps_parse_msg(&msg, &attr) < 0 ||
            wps_process_cred(&attr, &wps->cred))
        return -1;

    if (os_memcmp(wps->cred.mac_addr, wps->wps->dev.mac_addr, ETH_ALEN) !=
            0) {
        wpa_printf(MSG_DEBUG, "WPS: MAC Address in the Credential ("
                MACSTR ") does not match with own address (" MACSTR
                ")", MAC2STR(wps->cred.mac_addr),
                MAC2STR(wps->wps->dev.mac_addr));
        /*
         * In theory, this could be consider fatal error, but there are
         * number of deployed implementations using other address here
         * due to unclarity in the specification. For interoperability
         * reasons, allow this to be processed since we do not really
         * use the MAC Address information for anything.
         */
    }

    if (wps->wps->cred_cb) {
        wps->cred.cred_attr = cred - 4;
        wps->cred.cred_attr_len = cred_len + 4;
        wps->wps->cred_cb(wps->wps->cb_ctx, &wps->cred);
        wps->cred.cred_attr = NULL;
        wps->cred.cred_attr_len = 0;
    }

    return 0;
}


static int wps_process_creds(struct wps_data *wps, const u8 *cred[],
        size_t cred_len[], size_t num_cred)
{
    size_t i;

    if (wps->wps->ap)
        return 0;

    if (num_cred == 0) {
        wpa_printf(MSG_DEBUG, "WPS: No Credential attributes "
                "received");
        return -1;
    }

    for (i = 0; i < num_cred; i++) {
        if (wps_process_cred_e(wps, cred[i], cred_len[i]))
            return -1;
    }

    return 0;
}


static int wps_process_ap_settings_e(struct wps_data *wps,
        struct wps_parse_attr *attr,
        struct wpabuf *attrs)
{
    struct wps_credential cred;

    if (!wps->wps->ap)
        return 0;

    if (wps_process_ap_settings(attr, &cred) < 0)
        return -1;

    wpa_printf(MSG_INFO, "WPS: Received new AP configuration from "
            "Registrar");

    if (os_memcmp(cred.mac_addr, wps->wps->dev.mac_addr, ETH_ALEN) !=
            0) {
        wpa_printf(MSG_DEBUG, "WPS: MAC Address in the AP Settings ("
                MACSTR ") does not match with own address (" MACSTR
                ")", MAC2STR(cred.mac_addr),
                MAC2STR(wps->wps->dev.mac_addr));
        /*
         * In theory, this could be consider fatal error, but there are
         * number of deployed implementations using other address here
         * due to unclarity in the specification. For interoperability
         * reasons, allow this to be processed since we do not really
         * use the MAC Address information for anything.
         */
    }

    if (wps->wps->cred_cb) {
        cred.cred_attr = wpabuf_head(attrs);
        cred.cred_attr_len = wpabuf_len(attrs);
        wps->wps->cred_cb(wps->wps->cb_ctx, &cred);
    }

    return 0;
}


static enum wps_process_res wps_process_m2(struct wps_data *wps,
        const struct wpabuf *msg,
        struct wps_parse_attr *attr)
{
    wpa_printf(MSG_DEBUG, "WPS: Received M2");

    if (wps->state != RECV_M2) {
        wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                "receiving M2", wps->state);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps_process_registrar_nonce(wps, attr->registrar_nonce) ||
            wps_process_enrollee_nonce(wps, attr->enrollee_nonce) ||
            wps_process_uuid_r(wps, attr->uuid_r)) {
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps->wps->ap &&
            (wps->wps->ap_setup_locked || wps->dev_password == NULL)) {
        wpa_printf(MSG_DEBUG, "WPS: AP Setup is locked - refuse "
                "registration of a new Registrar");
        wps->config_error = WPS_CFG_SETUP_LOCKED;
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps_process_pubkey(wps, attr->public_key, attr->public_key_len) ||
            wps_process_authenticator(wps, attr->authenticator, msg) ||
            wps_process_device_attrs(&wps->peer_dev, attr)) {
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    wps->state = SEND_M3;
    return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m2d(struct wps_data *wps,
        struct wps_parse_attr *attr)
{
    wpa_printf(MSG_DEBUG, "WPS: Received M2D");

    if (wps->state != RECV_M2) {
        wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                "receiving M2D", wps->state);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    wpa_hexdump_ascii(MSG_DEBUG, "WPS: Manufacturer",
            attr->manufacturer, attr->manufacturer_len);
    wpa_hexdump_ascii(MSG_DEBUG, "WPS: Model Name",
            attr->model_name, attr->model_name_len);
    wpa_hexdump_ascii(MSG_DEBUG, "WPS: Model Number",
            attr->model_number, attr->model_number_len);
    wpa_hexdump_ascii(MSG_DEBUG, "WPS: Serial Number",
            attr->serial_number, attr->serial_number_len);
    wpa_hexdump_ascii(MSG_DEBUG, "WPS: Device Name",
            attr->dev_name, attr->dev_name_len);

    if (wps->wps->event_cb) {
        union wps_event_data data;
        struct wps_event_m2d *m2d = &data.m2d;
        os_memset(&data, 0, sizeof(data));
        if (attr->config_methods)
            m2d->config_methods =
                WPA_GET_BE16(attr->config_methods);
        m2d->manufacturer = attr->manufacturer;
        m2d->manufacturer_len = attr->manufacturer_len;
        m2d->model_name = attr->model_name;
        m2d->model_name_len = attr->model_name_len;
        m2d->model_number = attr->model_number;
        m2d->model_number_len = attr->model_number_len;
        m2d->serial_number = attr->serial_number;
        m2d->serial_number_len = attr->serial_number_len;
        m2d->dev_name = attr->dev_name;
        m2d->dev_name_len = attr->dev_name_len;
        m2d->primary_dev_type = attr->primary_dev_type;
        if (attr->config_error)
            m2d->config_error =
                WPA_GET_BE16(attr->config_error);
        if (attr->dev_password_id)
            m2d->dev_password_id =
                WPA_GET_BE16(attr->dev_password_id);
        wps->wps->event_cb(wps->wps->cb_ctx, WPS_EV_M2D, &data);
    }

    wps->state = RECEIVED_M2D;
    return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m4(struct wps_data *wps,
        const struct wpabuf *msg,
        struct wps_parse_attr *attr)
{
    struct wpabuf *decrypted;
    struct wps_parse_attr eattr;

    wpa_printf(MSG_DEBUG, "WPS: Received M4");

    if (wps->state != RECV_M4) {
        wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                "receiving M4", wps->state);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps_process_enrollee_nonce(wps, attr->enrollee_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg) ||
            wps_process_r_hash1(wps, attr->r_hash1) ||
            wps_process_r_hash2(wps, attr->r_hash2)) {
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    decrypted = wps_decrypt_encr_settings(wps, attr->encr_settings,
            attr->encr_settings_len);
    if (decrypted == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: Failed to decrypted Encrypted "
                "Settings attribute");
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    wpa_printf(MSG_DEBUG, "WPS: Processing decrypted Encrypted Settings "
            "attribute");
    if (wps_parse_msg(decrypted, &eattr) < 0 ||
            wps_process_key_wrap_auth(wps, decrypted, eattr.key_wrap_auth) ||
            wps_process_r_snonce1(wps, eattr.r_snonce1)) {
        wpabuf_free(decrypted);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }
    wpabuf_free(decrypted);

    wps->state = SEND_M5;
    return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m6(struct wps_data *wps,
        const struct wpabuf *msg,
        struct wps_parse_attr *attr)
{
    struct wpabuf *decrypted;
    struct wps_parse_attr eattr;

    wpa_printf(MSG_DEBUG, "WPS: Received M6");

    if (wps->state != RECV_M6) {
        wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                "receiving M6", wps->state);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps_process_enrollee_nonce(wps, attr->enrollee_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg)) {
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    decrypted = wps_decrypt_encr_settings(wps, attr->encr_settings,
            attr->encr_settings_len);
    if (decrypted == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: Failed to decrypted Encrypted "
                "Settings attribute");
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    wpa_printf(MSG_DEBUG, "WPS: Processing decrypted Encrypted Settings "
            "attribute");
    if (wps_parse_msg(decrypted, &eattr) < 0 ||
            wps_process_key_wrap_auth(wps, decrypted, eattr.key_wrap_auth) ||
            wps_process_r_snonce2(wps, eattr.r_snonce2)) {
        wpabuf_free(decrypted);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }
    wpabuf_free(decrypted);

    wps->state = SEND_M7;
    return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m8(struct wps_data *wps,
        const struct wpabuf *msg,
        struct wps_parse_attr *attr)
{
    struct wpabuf *decrypted;
    struct wps_parse_attr eattr;

    wpa_printf(MSG_DEBUG, "WPS: Received M8");

    if (wps->state != RECV_M8) {
        wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                "receiving M8", wps->state);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    if (wps_process_enrollee_nonce(wps, attr->enrollee_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg)) {
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    decrypted = wps_decrypt_encr_settings(wps, attr->encr_settings,
            attr->encr_settings_len);
    if (decrypted == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: Failed to decrypted Encrypted "
                "Settings attribute");
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }

    wpa_printf(MSG_DEBUG, "WPS: Processing decrypted Encrypted Settings "
            "attribute");
    if (wps_parse_msg(decrypted, &eattr) < 0 ||
            wps_process_key_wrap_auth(wps, decrypted, eattr.key_wrap_auth) ||
            wps_process_creds(wps, eattr.cred, eattr.cred_len,
                eattr.num_cred) ||
            wps_process_ap_settings_e(wps, &eattr, decrypted)) {
        wpabuf_free(decrypted);
        wps->state = SEND_WSC_NACK;
        return WPS_CONTINUE;
    }
    wpabuf_free(decrypted);

    wps->state = WPS_MSG_DONE;
    return WPS_CONTINUE;
}


static enum wps_process_res wps_process_wsc_msg(struct wps_data *wps,
        const struct wpabuf *msg)
{
    struct wps_parse_attr attr;
    enum wps_process_res ret = WPS_CONTINUE;

    wpa_printf(MSG_DEBUG, "WPS: Received WSC_MSG");

    if (wps_parse_msg(msg, &attr) < 0)
        return WPS_FAILURE;

    if (!wps_version_supported(attr.version)) {
        wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                attr.version ? *attr.version : 0);
        return WPS_FAILURE;
    }

    if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
        wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
        return WPS_FAILURE;
    }

    if (attr.msg_type == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
        return WPS_FAILURE;
    }

    switch (*attr.msg_type) {
        case WPS_M2:
            ret = wps_process_m2(wps, msg, &attr);
            break;
        case WPS_M2D:
            ret = wps_process_m2d(wps, &attr);
            break;
        case WPS_M4:
            ret = wps_process_m4(wps, msg, &attr);
            if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                wps_fail_event(wps->wps, WPS_M4);
            break;
        case WPS_M6:
            ret = wps_process_m6(wps, msg, &attr);
            if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                wps_fail_event(wps->wps, WPS_M6);
            break;
        case WPS_M8:
            ret = wps_process_m8(wps, msg, &attr);
            if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                wps_fail_event(wps->wps, WPS_M8);
            break;
        default:
            wpa_printf(MSG_DEBUG, "WPS: Unsupported Message Type %d",
                    *attr.msg_type);
            return WPS_FAILURE;
    }

    /*
     * Save a copy of the last message for Authenticator derivation if we
     * are continuing. However, skip M2D since it is not authenticated and
     * neither is the ACK/NACK response frame. This allows the possibly
     * following M2 to be processed correctly by using the previously sent
     * M1 in Authenticator derivation.
     */
    if (ret == WPS_CONTINUE && *attr.msg_type != WPS_M2D) {
        /* Save a copy of the last message for Authenticator derivation
        */
        wpabuf_free(wps->last_msg);
        wps->last_msg = wpabuf_dup(msg);
    }

    return ret;
}


static enum wps_process_res wps_process_wsc_ack(struct wps_data *wps,
        const struct wpabuf *msg)
{
    struct wps_parse_attr attr;

    wpa_printf(MSG_DEBUG, "WPS: Received WSC_ACK");

    if (wps_parse_msg(msg, &attr) < 0)
        return WPS_FAILURE;

    if (!wps_version_supported(attr.version)) {
        wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                attr.version ? *attr.version : 0);
        return WPS_FAILURE;
    }

    if (attr.msg_type == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
        return WPS_FAILURE;
    }

    if (*attr.msg_type != WPS_WSC_ACK) {
        wpa_printf(MSG_DEBUG, "WPS: Invalid Message Type %d",
                *attr.msg_type);
        return WPS_FAILURE;
    }

    if (attr.registrar_nonce == NULL ||
            os_memcmp(wps->nonce_r, attr.registrar_nonce, WPS_NONCE_LEN != 0))
    {
        wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
        return WPS_FAILURE;
    }

    if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
        wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
        return WPS_FAILURE;
    }

    if (wps->state == RECV_ACK && wps->wps->ap) {
        wpa_printf(MSG_DEBUG, "WPS: External Registrar registration "
                "completed successfully");
        wps_success_event(wps->wps);
        wps->state = WPS_FINISHED;
        return WPS_DONE;
    }

    return WPS_FAILURE;
}


static enum wps_process_res wps_process_wsc_nack(struct wps_data *wps,
        const struct wpabuf *msg)
{
    struct wps_parse_attr attr;

    wpa_printf(MSG_DEBUG, "WPS: Received WSC_NACK");

    if (wps_parse_msg(msg, &attr) < 0)
        return WPS_FAILURE;

    if (!wps_version_supported(attr.version)) {
        wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                attr.version ? *attr.version : 0);
        return WPS_FAILURE;
    }

    if (attr.msg_type == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
        return WPS_FAILURE;
    }

    if (*attr.msg_type != WPS_WSC_NACK) {
        wpa_printf(MSG_DEBUG, "WPS: Invalid Message Type %d",
                *attr.msg_type);
        return WPS_FAILURE;
    }

    if (attr.registrar_nonce == NULL ||
            os_memcmp(wps->nonce_r, attr.registrar_nonce, WPS_NONCE_LEN != 0))
    {
        wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
        wpa_hexdump(MSG_DEBUG, "WPS: Received Registrar Nonce",
                attr.registrar_nonce, WPS_NONCE_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: Expected Registrar Nonce",
                wps->nonce_r, WPS_NONCE_LEN);
        return WPS_FAILURE;
    }

    if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
        wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
        wpa_hexdump(MSG_DEBUG, "WPS: Received Enrollee Nonce",
                attr.enrollee_nonce, WPS_NONCE_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: Expected Enrollee Nonce",
                wps->nonce_e, WPS_NONCE_LEN);
        return WPS_FAILURE;
    }

    if (attr.config_error == NULL) {
        wpa_printf(MSG_DEBUG, "WPS: No Configuration Error attribute "
                "in WSC_NACK");
        return WPS_FAILURE;
    }

    wpa_printf(MSG_DEBUG, "WPS: Registrar terminated negotiation with "
            "Configuration Error %d", WPA_GET_BE16(attr.config_error));

    switch (wps->state) {
        case RECV_M4:
            wps_fail_event(wps->wps, WPS_M3);
            break;
        case RECV_M6:
            wps_fail_event(wps->wps, WPS_M5);
            break;
        case RECV_M8:
            wps_fail_event(wps->wps, WPS_M7);
            break;
        default:
            break;
    }

    /* Followed by NACK if Enrollee is Supplicant or EAP-Failure if
     * Enrollee is Authenticator */
    wps->state = SEND_WSC_NACK;

    return WPS_FAILURE;
}


enum wps_process_res wps_enrollee_process_msg(struct wps_data *wps,
        enum wsc_op_code op_code,
        const struct wpabuf *msg)
{

    wpa_printf(MSG_DEBUG, "WPS: Processing received message (len=%lu "
            "op_code=%d)",
            (unsigned long) wpabuf_len(msg), op_code);

    if (op_code == WSC_UPnP) {
        /* Determine the OpCode based on message type attribute */
        struct wps_parse_attr attr;
        if (wps_parse_msg(msg, &attr) == 0 && attr.msg_type) {
            if (*attr.msg_type == WPS_WSC_ACK)
                op_code = WSC_ACK;
            else if (*attr.msg_type == WPS_WSC_NACK)
                op_code = WSC_NACK;
        }
    }

    switch (op_code) {
        case WSC_MSG:
        case WSC_UPnP:
            return wps_process_wsc_msg(wps, msg);
        case WSC_ACK:
            return wps_process_wsc_ack(wps, msg);
        case WSC_NACK:
            return wps_process_wsc_nack(wps, msg);
        default:
            wpa_printf(MSG_DEBUG, "WPS: Unsupported op_code %d", op_code);
            return WPS_FAILURE;
    }
}
